CN102479489A

CN102479489A - Semiconductor integrated circuit and operation method thereof

Info

Publication number: CN102479489A
Application number: CN2011103790234A
Authority: CN
Inventors: 北川雄平; 南一保
Original assignee: Renesas Electronics Corp
Current assignee: Renesas Electronics Corp
Priority date: 2010-11-26
Filing date: 2011-11-25
Publication date: 2012-05-30
Anticipated expiration: 2031-11-25
Also published as: US20120133291A1; JP5666268B2; KR20120059385A; US8536806B2; CN102479489B; JP2012114316A; KR101886872B1

Abstract

A semiconductor integrated circuit and an operation method are provided, by which a most suitable driving voltage can be generated even through aiming at the situations, such as a temperature variation, the characteristics derivation of a light-emitting element, etc. to thereby reduce the system power consumption. A DC-DC converter supplies an output voltage to a plurality of channels of a light emitting device array in common. A current driver has a plurality of driver units which drive the channels. Each of the driver units includes a drive transistor and a detector which detects an abnormality of a drive current. A logic unit generates digital data is in response to a plurality of detection signals and supplies the same to a D/A converter. An analog reference voltage of the D/A converter is supplied to the DC-DC converter. The logic unit executes a calibration operation which determines digital data for setting the minimum output DC voltage at the normal operation of all the channels by sequential updating of the digital data.

Description

SIC (semiconductor integrated circuit) and method of work thereof

Technical field

The present invention relates to be used for the SIC (semiconductor integrated circuit) and the method for work thereof of controlling and driving light-emitting component; More specifically; Even the situation such as characteristic deviation that relate to temperature variation and light-emitting component also can generate only driving voltage effectively, reduce the technology of the power consumption of system.

Background technology

Light emitting diode (LED) is luminous semiconductor element through on positive dirction, applying voltage, and principle of luminosity is to utilize electroluminescence (EL) effect, organic EL (OLED: Organic Light Emitting Diode) also belong to light emitting diode (LED).

Light emitting diode utilizes semi-conductive PN junction structure since luminous be to be directly converted to luminous energy to the energy that electronics has, so need not be by means of heat energy and kinetic energy.Electronics and hole are flow through conduction band and valence band respectively because of positive dirction applies voltage, and electronics and hole are crossed forbidden band (band gap) and combined once more near the PN junction part.When combining once more, the energy that roughly is equivalent to the forbidden band bandwidth is that light is launched as photon.The light wavelength of sending is by the band gap decision of semiconductor material, bill coloured light basically.In addition, through on the surface of the look that turns blue, purple, ultraviolet light emitting diode, applying the light emitting diode that fluorescent paint also can be made various Neutral colour such as white, incandescent light color.

In order to make lumination of light emitting diode, must between anode and negative electrode, apply the positive dirction voltage V of PN junction _FAbove service voltage, the luminous quantity of light emitting diode is corresponding with the positive dirction magnitude of current.In addition, the positive dirction voltage V of light emitting diode _FDifferent because of illuminant colour, infrared is about 1.4V, and red, orange, yellow, green is about 2.1V, and white, blueness are about 3.5V, and ultraviolet ray is about 4.5V-6V.

Illuminant colour through with light emitting diode uses following semiconductor material accordingly, can make the light emitting diode of various illuminant colours.

Gallium aluminium arsenic (AlGaAs)-infrared ray, redness

Gallium arsenic phosphide (GaAsP)-red, orange, yellow

InGaN (InGaN)/gallium nitride (GaN)/aluminium gallium nitride alloy (AlGaN)-(orange, yellow), green, blueness, purple, ultraviolet ray

Gallium phosphide (GaP)-redness, yellow, green

Zinc selenide (ZnSe)-green, blue

AlGaInP (AlGaInP)-orange, yellowish orange, yellow, green

On the other hand, white light is the light of being realized by the continuous spectrum of whole visible light wave range, and light emitting diode only sends specific range of wavelengths, so can not realize the white light-emitting diode on the script meaning.The coloured light diode but the simulation that has proposed to utilize human eye character is turned white.This light emitting diode has utilized the three primary colours of light to mix, have the mixing of two kinds of colors of complementary color relation it seems that human eye also be the such character of white, so its substitute as white light.

For example, the white light-emitting diode of fluorophor mode is the mode of the light emitting diode of blue or shorter than its wavelength light and fluorophor combination, becomes the structure that has covered the chip of light emitting diode with fluorophor.If light it, then can obtain the light of fluorescence and the mixed light of the light of the light emitting diode that has seen through fluorophor, can obtain white light through adjustment wavelength of fluorescence, fluorophor thickness etc.

Blue yellow simulation white light-emitting diode is the main flow of present white light-emitting diode; Through combining the fluorophor and the blue LED of the fluorescence of the yellow of sending the high wavelength of visual sensitivity, realize visually very bright white light-emitting diode.

In addition, light emitting diode (LED) is because power consumption is low, the life-span is long, small-sized, so in a lot of electronic installations, use.As concrete application; The backlight, light-emitting diode display of the guide demonstration, large-scale tv, billboard on signalling means, the station relevant with traffic and airport etc., LCD TV and notebook computer, illuminating LED illumination outside the room etc. are within doors arranged, and its range of application enlarges just day by day now.

In recent years, each company of semiconductor maker has released the driver of driving as the led array of the white light-emitting diode of large-scale Backlight For Liquid Crystal Display Panels.Can the parallel drive a plurality of LED strings of this driver (series), each LED string in a plurality of LED strings a plurality of light emitting diodes (LED) that can be connected in series.

In following patent documentation 1, put down in writing a kind of light-emitting component drive apparatus that can drive a plurality of light-emitting component series; Comprise a plurality of light-emitting components in each series; This light-emitting component drive apparatus can irrespectively carry out constant-current driving with the characteristic deviation of light-emitting component, reduces power loss.The common high voltage that generates from the Switching power circuit that boosts of supplying with of a plurality of anodes of a plurality of light-emitting components of the higher level who in a plurality of light-emitting component series, comprises, a plurality of negative electrodes of a plurality of light-emitting components of the subordinate that utilizes a plurality of constant-flow drivers to drive respectively to comprise in a plurality of light-emitting component series.And then, to select circuit supply with subordinate a plurality of light-emitting components a plurality of negative electrodes a plurality of voltages, promptly be applied to a plurality of a plurality of voltages of decide on the current driver, select circuit to select minimum voltages as detection voltage and feed back to control circuit from a plurality of voltages.Detect the control signal that voltage equates with reference voltage because control circuit generates to make,, detection voltage is equated with reference voltage so the Switching power circuit that boosts is controlled high-tension size in response to control signal.The value of reference voltage is set in the active region (the specific activity zone has some more than needed with the border of zone of saturation) for and is made transistor work, so that steady current flows through the transistor of a plurality of constant-flow drivers reliably.Its result automatically is controlled to minimum voltage to the high voltage of the Switching power circuit that boosts and equates with reference voltage, so even a plurality of LED element has characteristic deviation, each LED element also can be luminous fully, and can reduce the loss of a plurality of constant-flow drivers.

In following non-patent literature 1, having put down in writing a kind of is the high efficiency driver of the led array of white light-emitting diode as the white light-emitting diode of the large-scale LCD design of light source.Led array can parallel connection be formed into 8 strings, has 10 LED coupled in series in each string.To the common output voltage that generates from (step-up) controller that boosts that constitutes by inductor, power MOS transistor, commutation diode and capacitor of supplying with of a plurality of anodes of the higher level's of 8 strings LED, utilize a plurality of current sources to drive a plurality of negative electrodes of a plurality of LED of the subordinate of 8 strings respectively.Each current source in a plurality of current sources is made up of differential amplifier, N channel power MOS transistor and resistance.Through automatically selected the driving voltage of a plurality of current sources by boost pressure controller is the minimum voltage of a plurality of feedback voltages, the adjustment output voltage.

< patent documentation 1>TOHKEMY 2003-332624 communique

http://www.maxim-ic.com/datasheet/index.mvp/id/5445

(retrieval on October 15th, 2010)

Summary of the invention

(problem that invention will solve)

Before accomplishing the present invention, the inventor is to researching and developing as the controlling and driving SIC (semiconductor integrated circuit) of the White LED array of the large-scale Backlight For Liquid Crystal Display Panels of use in television receiver etc.

Fig. 1 is illustrated in to accomplish before the present invention, is waited the figure that constitutes of the controlling and driving SIC (semiconductor integrated circuit) of the White LED array that has carried out analysis by the inventor.

The SIC (semiconductor integrated circuit) 1 of White LED array shown in Figure 1 is made up of constant-flow driver 20, logical block 30 and the reference voltage generation portion 40 of boost DC-

DC converter

10,8 raceway grooves (8 string), and logical block 30 comprises 12 (4096 tone) light adjusting controllers 31.

That kind shown in the image pattern 1 has the for example input dc voltage V of the voltage range of 10V～26.0V to SIC (semiconductor integrated circuit) 1 supply _IN, and SIC (semiconductor integrated circuit) 1 can be with inductor 2, N channel power MOS transistor 3, for example commutation diode 4, smmothing capacitor 5 and the feedback circuit 6 of schottky diode be connected in conduct.One end of inductor 2 and input dc voltage V _INConnect; The other end of inductor 2 is connected with the drain terminal of N channel power MOS transistor 3 and the anode of commutation diode 4, and the negative electrode of commutation diode 4 is connected with a plurality of anodes of the higher level's of feedback circuit 6, smmothing capacitor 5 and 8 raceway grooves LED element D11...D81.The lead-out terminal OUT1...OUT8 of the actuator unit 21...28 of 8 raceway grooves that a plurality of negative electrodes of the LED element D16...D86 of the subordinate of 8 raceway grooves and constant-flow driver 20 are inner is connected, between terminal SO1...SO8 and earthing potential are set in the constant current of the actuator unit 21...28 of 8 raceway grooves of constant-flow driver 20, is connected constant current setting resistance R s respectively.

The actuator unit 21 of constant-flow driver 20 is made up of differential amplifier 211 and N channel power MOS transistor 212; Non-inverting input to differential amplifier 211 is supplied with reference voltage Vref; The lead-out terminal of differential amplifier 211 is connected with the gate terminal of N channel power MOS transistor 212; The source terminal of N channel power MOS transistor 212 is connected with the end that resistance R s is set in the reversed input terminal of differential amplifier 211 and constant current; The other end that resistance R s is set in constant current is connected with earthing potential, and the drain terminal of N channel power MOS transistor 212 is connected via the negative electrode of the LED element D16 of the subordinate of the lead-out terminal OUT1 of actuator unit 21 and first raceway groove.

Because the differential amplifier 211 and the N channel power MOS transistor 212 of the actuator unit 21 of constant-flow driver 20 are worked as voltage follower (follower); So reference voltage Vref is supplied with at the two ends through set resistance R s to constant current, sets the first raceway groove LED drive current I of the LED element D11...D16 that flows into first raceway groove _LED<1>Current value.The actuator unit 22 (not shown) of other raceway groove of constant-flow driver 20 inside ... actuator unit 28 also all fully likewise is made up of differential amplifier that carries out voltage follower work and N channel power MOS transistor with actuator unit 21, sets other the second raceway groove LED drive current I _LED<2>(not shown) ... the 8th raceway groove LED drive current I _LED<8>Current value.

And then; Supply with the voltage of a plurality of negative electrodes of LED element D16...D86 of the subordinate of 8 raceway grooves to a plurality of reversed input terminals of the error amplifier 11 of boost DC-DC converter 10, i.e. a plurality of driving output voltages of the lead-out terminal OUT1...OUT8 of the actuator unit 21...28 of constant-flow driver 20.

Logical block 30 is synchronously supplied with 1 bit serial brightness adjustment control data to light adjusting controller 31 with light modulation clock DPWMCLK.Light adjusting controller 31 is supplied with light modulation pulse width modulation drive signal DPWMO < 1>to the actuator unit 21...28 of constant-flow driver 20 ... < 8>in response to the brightness adjustment control data.Light modulation pulse width modulation drive signal DPWMO < 1>... each drive signal < 8>can utilize during the high value (high level) with low value (low level) during the luminosity of recently adjusting LED.

Reference voltage generation portion 40 is passing through saturation voltage V between the drain-source of the N channel power MOS transistor 212 of the actuator unit 21...28 of the reference voltage Vref of the non-inverting input of the differential amplifier 211 of the actuator unit 21...28 of constant-flow driver 20 and constant-flow driver 20 _SATThe voltage Vref+V that adds that obtains of difference (offset) addition _SAT, as reference voltage V _REFNon-inverting input to the error amplifier 11 of boost DC-DC converter 10 is supplied with.

Boost DC-DC converter 10 is made up of error amplifier 11 and controller 12.Non-inverting input to error amplifier 11 is supplied with the reference voltage V that generates from reference voltage generation portion 40 _REF, supply with a plurality of driving output voltages of the lead-out terminal OUT1...OUT8 of actuator unit 21...28 to a plurality of reversed input terminals of error amplifier 11, supply with the feedback voltage V that generates from feedback circuit 6 to the last reversed input terminal of error amplifier 11 _FBIn addition, through two divider resistance R1 that utilize feedback circuit 6, the output dc voltage V that boosts that R2 generates the negative electrode from commutation diode 4 _OUTDividing potential drop and generate feedback voltage V _FB

The switching regulaor (switching regulator) that constitutes by boost DC-DC converter 10, inductor 2, N channel power MOS transistor 3, commutation diode 4 and smmothing capacitor 5; Through during the connection that makes power MOS transistor 3 and between the off period of power MOS transistor 3 repeatedly, carry out from the negative electrode of commutation diode 4 and generate the output dc voltage V that boosts _OUTPulse-length modulation (PWM) action.

If the inductance of inductor 2 is L, the time is t, then during the connection of power MOS transistor 3, via inductor 2 and power MOS transistor 3 from input dc voltage V _INThe electric current that flows and to provide to earthing potential by following formula:

I _ON=V _INT/L formula (1)

Between the off period of the power MOS transistor 3 after during connecting, via inductor 2 and commutation diode 4 from input dc voltage V _INThe electric currents that flow and provide to smmothing capacitor 5 by following formula:

I _OFF=(V _IN-V _OUT) t/L formula (2)

If during the connection of power MOS transistor 3 be T _ON, power MOS transistor 3 off period between be T _OFF, then the boundary during two must be equated with the electric current that is provided by formula (2) by the electric current that formula (1) provides.Therefore, obtain following formula.

V _INT _ON/ L=(V _IN-V _OUT) T _OFF/ L formula (3)

If launch this formula (3) then obtain the relation of following formula.

V _OUT=(1+ (T _ON/ T _OFF)) V _INFormula (4)

This formula (4) illustrates, and the switching regulaor generation that is made up of boost DC-DC converter 10, inductor 2, N channel power MOS transistor 3, commutation diode 4 and smmothing capacitor 5 has than input dc voltage V _INThe output dc voltage V of the big voltage of voltage _OUT

On the other hand, owing to supply with output dc voltage V to the last reversed input terminal of error amplifier 11 _OUTTwo divider resistance R1 that utilize feedback circuit 6, R2 dividing potential drop and the feedback voltage V that generates _FB, supply with the reference voltage V that generates from reference voltage generation portion 40 to non-inverting input of error amplifier 11 _REFSo error amplifier 11 is worked and is generated output dc voltage V _OUTSo that feedback voltage V _FBMagnitude of voltage and reference voltage V _REFMagnitude of voltage consistent.That is, controller 12 utilize between rising stage of triangular waveform of pulse-length modulation (PWM) and the ratio between decrement phase confirm to connect during T _ONAnd T between the off period _OFFRatio so that these two magnitude of voltage unanimities.

With the record of the record of above-mentioned patent documentation 1 and above-mentioned non-patent literature 1 roughly likewise; Supply with the voltage of a plurality of negative electrodes of LED element D16...D86 of the subordinate of 8 raceway grooves to a plurality of reversed input terminals of the error amplifier 11 of boost DC-DC converter 10; Be a plurality of driving output voltages of lead-out terminal OUT1...OUT8 of the actuator unit 21...28 of constant-flow driver 20, the minimum voltage that error amplifier 11 is selected in a plurality of driving output voltages.And then error amplifier 11 control controllers 12 are so that the magnitude of voltage of selecteed minimum voltage and the reference voltage V of boosting _REF(=Vref+V _SAT) equate, so output dc voltage V _OUTMagnitude of voltage finally adjusted.Therefore, output dc voltage V _OUTMagnitude of voltage automatically be controlled to minimum voltage and reference voltage V in a plurality of driving output voltages _REF(=Vref+V _SAT) equate, so even a plurality of LED element D11...D16～D81...D86 has characteristic deviation, each LED element also can be luminous fully, and can reduce the loss of the actuator unit 21...28 of constant-flow driver 20.

In the SIC (semiconductor integrated circuit) 1 of White LED array shown in Figure 1, rise at Yin Wendu, the characteristic deviation of LED element etc. former thereby make the positive dirction voltage V of the PN junction of a plurality of LED element D11...D16～D81...D86 _FWhen reducing, the magnitude of voltage of the minimum voltage of being selected by error amplifier 11 increases.Therefore, the error amplifier 11 of boost DC-DC converter 10 reduces output dc voltage V with controller 12 _OUTMagnitude of voltage, to be reduced to reference voltage V to the magnitude of voltage of the selection minimum voltage that has been increased _REF(=Vref+V _SAT).

And then, in the SIC (semiconductor integrated circuit) 1 of White LED array shown in Figure 1, descend, the characteristic deviation of LED element etc. former thereby make the positive dirction voltage V of the PN junction of a plurality of LED element D11...D16～D81...D86 at Yin Wendu _FDuring increase, the magnitude of voltage of the minimum voltage of being selected by error amplifier 11 reduces.Therefore, the error amplifier 11 of boost DC-DC converter 10 makes output dc voltage V with controller 12 _OUTMagnitude of voltage rise, to increase to reference voltage V to the magnitude of voltage of the selection minimum voltage that has been lowered _REF(=Vref+V _SAT).But, owing to output dc voltage V in the switching regulaor of Fig. 1 _OUTRising the upper limit is arranged, so can not make output dc voltage V _OUTMagnitude of voltage rise to more than the rising upper limit.

Therefore, in the SIC (semiconductor integrated circuit) 1 of White LED array shown in Figure 1, descend because of extremely temperature, the characteristic deviation of the extreme of LED element etc. former thereby make the positive dirction voltage V of the PN junction of a plurality of LED element D11...D16～D81...D86 _FWhen extremely increasing, can not increase to reference voltage V to the magnitude of voltage of the selection minimum voltage that has been lowered _REF(=Vref+V _SAT).

Its result, the first raceway groove LED drive current I _LED<1>... the 8th raceway groove LED drive current I _LED<8>The initial normal constant current value of each current value ratio low.Therefore; The voltage drop that constant current is set between the two ends of resistance R s significantly reduces than reference voltage Vref, so the differential amplifier 211 of the actuator unit 21 of constant-

flow driver

20 and 212 work of N-channel MOS transistor increase to reference voltage Vref with the voltage drop of setting the constant current that has reduced between resistance R s two ends.That is, the differential amplifier 211 of actuator unit 21 is to the output voltage of the extremely high value of the grid supply of N-channel MOS transistor 212, to compensate the first raceway groove LED drive current I _LED<1>Reduce.

But; With reducing likewise of the magnitude of voltage of selecting minimum voltage; The lead-out terminal OUT1 of the actuator unit 21 that is connected with the negative electrode of the LED element D16 of the subordinate of first raceway groove; Being the magnitude of voltage that first raceway groove of the drain terminal of N-channel MOS transistor 212 drives output voltage, also is to compare reference voltage V _REF(=Vref+V _SAT) much lower magnitude of voltage.Therefore, to the gate drive voltage of the quite high value of the grid supply of MOS transistor 212, but to supplying with voltage between quite low source drain between the source drain of MOS transistor 212.

Therefore; Under the supply situation of such WV; Work that MOS transistor 212 can not be in the zone of saturation of the MOS transistor that is fit to obtain constant-current characteristics (leakage current basically and between source drain independent from voltage and be constant zone), and (leakage current depends on voltage between source drain and the zone that changes basically) work in the range of linearity of the MOS transistor that is not suitable for obtaining constant-current characteristics.Its result is even the differential amplifier 211 of actuator unit 21 can not compensate the first raceway groove LED drive current I to the output voltage of the extremely high value of the grid supply of N-channel MOS transistor 212 _LED<1>Reduce the first raceway groove LED drive current I _LED<1>Can reduce.The actuator unit 22 (not shown) of other raceway groove that constant-flow driver 20 is inner ... actuator unit 28, also all with actuator unit 21 fully likewise, other the second raceway groove LED drive current I _LED<2>(not shown) ... the 8th raceway groove LED drive current I _LED<8>Each current value also the normal constant current value than initial is low, through before accomplishing the present invention, wait the analysis of carrying out can understand this point by inventor.

In addition, owing to the first raceway groove LED drive current I according to actuator unit 21...28 _LED<1>... the 8th raceway groove LED drive current I _LED<8>Driving condition, select continually, switch to and be set at and reference voltage V _REFThe position of the voltage that equates is lead-out terminal OUT1...OUT8 and feedback voltage V _FBIn any, so system is unstable, be absorbed in unsettled work easily, this point also can be understood through analysis before accomplishing the present invention, that undertaken by inventor etc.

The present invention just be based on above that kind, before accomplishing the present invention, wait the result of the analysis of carrying out to accomplish by inventor.

Therefore, the objective of the invention is to,, reduce the light-emitting component controlling and driving of the power consumption of system and use SIC (semiconductor integrated circuit) even provide situation such as characteristic deviation also can generate only driving voltage to temperature variation and light-emitting component.

Above-mentioned purpose and novel feature with other of the present invention can clearly be seen that from description of the invention and accompanying drawing.

(with the means of solve problem)

If the summary of the representative solution in the invention disclosed among the application is described briefly, then is described below.

That is, representational embodiment of the present invention is a kind of SIC (semiconductor integrated circuit) (1), a plurality of raceway grooves that can the parallel drive light-emitting device array.

Above-mentioned SIC (semiconductor integrated circuit) comprises DC-DC transducer (10), current driver (20), logical block (30) and D/A transducer (50).

Above-mentioned DC-DC transducer is jointly supplied with input dc voltage (V to a plurality of end (ANODE) of above-mentioned a plurality of raceway grooves of above-mentioned light-emitting device array _IN) boost or step-down and the output dc voltage (V that generates _OUT).

Above-mentioned current driver has a plurality of actuator units (21...28) of a plurality of other end (CATHODE) of the above-mentioned a plurality of raceway grooves that drive above-mentioned light-emitting device array.

Each actuator unit in above-mentioned a plurality of actuator unit comprises: drive above-mentioned light-emitting device array each raceway groove each other end driving transistors (212) and detect the unusual detecting device (213) of the drive current of above-mentioned driving transistors.

A plurality of detection signals (LIMIT < 1>... < 8 >) that above-mentioned logical block generates in response to a plurality of above-mentioned detecting device from above-mentioned a plurality of actuator units of above-mentioned current driver; Generate numerical data (DATA_VREF < 6:0 >), and supply to the input terminal of above-mentioned D/A transducer.

Above-mentioned D/A transducer generates aanalogvoltage in response to above-mentioned numerical data, as reference voltage (V _REF) supply to above-mentioned DC-DC transducer.

Above-mentioned logical block is through the renewal one by one of above-mentioned numerical data; Carry out to confirm the calibration operation of above-mentioned numerical data, this numerical data is used for setting from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices minimum above-mentioned output dc voltage (with reference to Fig. 2) during the above-mentioned unusual whole raceway groove operate as normal of not shown above-mentioned drive current all.

(effect of invention)

If the effect that is obtained by the representative solution in the invention disclosed among the application is described briefly, then is described below.

That is,,, can reduce the power consumption of system even also can generate only driving voltage owing to be directed against the situation such as characteristic deviation of temperature variation and light-emitting component according to the present invention.

Description of drawings

Fig. 2 is the figure of formation that the controlling and driving SIC (semiconductor integrated circuit) of 1 White LED array is shown according to the embodiment of the present invention.

Fig. 3 illustrates to be used for explaining the output dc voltage V that is carried out by 1 controlling and driving SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2 _OUTThe figure of waveform of each several part of SIC (semiconductor integrated circuit) 1 of calibration operation.

If Fig. 4 illustrates the driving duration of work of D11...D16～D81...D86 of the White LED array that 1 controlling and driving SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2 carries out through preset time, then carry out output dc voltage V shown in Figure 3 termly _OUTThe figure of state of calibration operation.

Fig. 5 illustrates 2 the output dc voltage V according to the embodiment of the present invention that carries out in the controlling and driving SIC (semiconductor integrated circuit) 1 of the present invention shown in Figure 2 _OUTThe figure of treatment scheme of calibration operation.

Fig. 6 is the figure of formation that the controlling and driving SIC (semiconductor integrated circuit) of 3 White LED array is shown according to the embodiment of the present invention.

Fig. 7 is the figure of formation that the controlling and driving SIC (semiconductor integrated circuit) of 4 White LED array is shown according to the embodiment of the present invention.

Fig. 8 is the figure of formation that the controlling and driving SIC (semiconductor integrated circuit) of 5 White LED array is shown according to the embodiment of the present invention.

(description of reference numerals)

1: SIC (semiconductor integrated circuit); 2: inductor; 3:N channel power MOS transistor; 4: commutation diode; 5: smmothing capacitor; 6: feedback circuit; 7:P channel power MOS transistor; 8: commutation diode; D11...D16～D81...D86:LED element; 10: boost DC-DC converter; 11: error amplifier; 12: controller; 20: constant-flow driver; 21...28: actuator unit; 211: differential amplifier; The 212:N channel MOS transistor; 213: the abnormality detection comparer; 30: logical block; 31: light adjusting controller; 32: counter controls portion; 33: up-down counter; 50: reference voltage generates the D/A transducer; OUT1...OUT8: lead-out terminal; SO1...SO8: terminal is set in constant current; Rs: resistance is set in constant current

Embodiment

1: the summary of embodiment

The summary of the representative embodiments in the invention disclosed among the application at first, is described.

To in the summary description of representative embodiments, adding bracket only is to be used for the content that notion comprised of inscape of this Reference numeral of illustration band as the Reference numeral of reference.

(1) representational embodiment of the present invention is a kind of SIC (semiconductor integrated circuit) (1), a plurality of raceway grooves that can the parallel drive light-emitting device array.

Above-mentioned logical block is through the renewal one by one of above-mentioned numerical data; Carry out to confirm the calibration operation of above-mentioned numerical data, this numerical data is used for setting from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices minimum above-mentioned output dc voltage (with reference to Fig. 2) the during operate as normal of above-mentioned unusual whole raceway grooves of not shown above-mentioned drive current all.

According to above-mentioned embodiment, even be directed against the change that the situation such as characteristic deviation of temperature variation and light-emitting component also can reduce the luminosity of light-emitting component.

In preferred embodiment; Before the above-mentioned calibration operation of execution; The above-mentioned numerical data that above-mentioned logical block handle is set predetermined initial value for supplies to the above-mentioned input terminal of above-mentioned D/A transducer, and above-mentioned then logical block begins the execution (with reference to Fig. 2) of above-mentioned calibration operation.

Another preferred embodiment in, if the driving duration of work of above-mentioned a plurality of raceway grooves that drives above-mentioned light-emitting device array at above-mentioned current driver through preset time, then above-mentioned logical block is carried out above-mentioned calibration operation (with reference to Fig. 4) termly.

Another preferred embodiment in; Before the above-mentioned execution of above-mentioned calibration operation; Above-mentioned logical block is supplied with the above-mentioned numerical data of setting above-mentioned predetermined initial value for to the above-mentioned input terminal of above-mentioned D/A transducer; When having confirmed the operate as normal of above-mentioned whole raceway grooves through the above-mentioned execution of above-mentioned calibration operation, above-mentioned logical block is set above-mentioned numerical data for than the above-mentioned predetermined little value of initial value one by one once more then.

After the operate as normal of the above-mentioned execution above-mentioned whole raceway grooves unconfirmed that pass through above-mentioned calibration operation the time, reset into the value of above-mentioned numerical data the value (with reference to Fig. 3, Fig. 5) under the state of the last operate as normal of having confirmed above-mentioned whole raceway grooves.

In preferred embodiment; Above-mentioned each actuator unit in above-mentioned a plurality of actuator unit also comprises differential amplifier (211); Its non-inverting input is supplied to reference voltage (Vref); Reversed input terminal is connected with the common terminal of above-mentioned driving transistors, and lead-out terminal is connected with control input end of above-mentioned driving transistors.

Between the above-mentioned common terminal of the above-mentioned reversed input terminal of the above-mentioned differential amplifier (211) of above-mentioned each actuator unit and above-mentioned driving transistors and earthing potential, can be connected constant current and set resistance (Rs).

Some connection the in above-mentioned control input end of input terminal of the above-mentioned detecting device of above-mentioned each actuator unit and above-mentioned driving transistors and the above-mentioned common terminal, supply with detection judgment standard voltage (V to another input terminal of the above-mentioned detecting device of above-mentioned each actuator unit _LIM) (with reference to Fig. 2, Fig. 6).

In another preferred embodiment; It is characterized in that above-mentioned logical block comprises: preserve the counter (33) of the value of above-mentioned numerical data and in response to from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices and upgrade the counter controls portion (32) (with reference to Fig. 2, Fig. 6) of the value of the above-mentioned numerical data of preserving in the above-mentioned counter one by one.

In another preferred embodiment, above-mentioned logical block also comprises the light adjusting controller (31) that generates a plurality of light modulation pulse width modulated driving signal (DPWMO < 1>... < 8 >).

It is characterized in that, utilize the above-mentioned a plurality of light modulation pulse width modulated driving signal that generate from above-mentioned light adjusting controller to activate above-mentioned a plurality of actuator unit (with reference to Fig. 2, Fig. 6).

In a preferred embodiment again, it is characterized in that above-mentioned light adjusting controller utilization disperses type of drive to generate above-mentioned a plurality of light modulation pulse width modulated driving signal (with reference to Fig. 2, Fig. 6) constantly in different generation each other.

In concrete embodiment, above-mentioned DC-DC transducer can be connected with inductor (2), power MOS transistor (3), smmothing capacitor (5) in the outside of above-mentioned SIC (semiconductor integrated circuit).

Above-mentioned DC-DC transducer is through drive above-mentioned power MOS transistor repeatedly during connecting and between the off period, above-mentioned DC-DC transducer generates above-mentioned output dc voltage (with reference to Fig. 2, Fig. 6).

In the most concrete embodiment, it is characterized in that above-mentioned a plurality of actuator units of above-mentioned constant-flow driver can drive above-mentioned a plurality of raceway grooves (with reference to Fig. 2, Fig. 6) of the above-mentioned light-emitting device array that is made up of a plurality of light emitting diodes with PN junction.

(2) the representational embodiment of another aspect of the present invention is the method for work of a kind of SIC (semiconductor integrated circuit) (1), a plurality of raceway grooves that this SIC (semiconductor integrated circuit) can the parallel drive light-emitting device array.

Above-mentioned DC-DC transducer is jointly supplied with input dc voltage (V to a plurality of end (ANODE) of above-mentioned a plurality of raceway grooves of above-mentioned light-emitting device array _IN) boost and the output dc voltage (V that generates _OUT).

Above-mentioned current driver has a plurality of actuator units (21...28) of a plurality of other end (CATHODE) of above-mentioned a plurality of raceway grooves that can drive above-mentioned light-emitting device array.

2: the details of embodiment

Below, the further explain embodiment.In addition, in the whole accompanying drawings that are used for explaining the best mode that carries out an invention, give identical Reference numeral, omit its repeat specification having with the parts of above-mentioned figure identical function.

(embodiment 1)

(formation of SIC (semiconductor integrated circuit))

The SIC (semiconductor integrated circuit) 1 of White LED array shown in Figure 2 generates D/A transducer 50 formations by constant-flow driver 20, logical block 30 and the reference voltage of boost DC-

DC converter

10,8 raceway grooves (8 string), and logical block 30 comprises 12 (4096 tone) light adjusting controllers 31, counter controls portion 32 and up-down counters 33.For example, in the example of Fig. 2, input dc voltage V _INVoltage range be the lower voltage of 10V～26.0V, so DC-DC transducer 10 is step-up DC-DC transducers.As another example, input dc voltage V _INBe during than higher voltage, DC-DC transducer 10 is buck DC-DC converters.As an example again, input dc voltage V _INWhen changing at lower voltage with between than higher voltage, DC-DC transducer 10 is buck-boost type DC-DC transducers.

(switching regulaor)

That kind shown in the image pattern 2 has the for example input dc voltage V of the voltage range of 10V～26.0V to SIC (semiconductor integrated circuit) 1 supply _IN, and in order to constitute switching regulaor, SIC (semiconductor integrated circuit) 1 can be with inductor 2, N channel power MOS transistor 3, for example commutation diode 4, smmothing capacitor 5 and the feedback circuit 6 of schottky diode be connected in conduct.One end of inductor 2 and input dc voltage V _INConnect; The other end of inductor 2 is connected with the drain terminal of power MOS transistor 3 and the anode of commutation diode 4, and the negative electrode of commutation diode 4 is connected with a plurality of anodes (ANODE) of the higher level's of feedback circuit 6, smmothing capacitor 5 and 8 raceway grooves LED element D11...D81.The lead-out terminal OUT1...OUT8 of the actuator unit 21...28 of 8 raceway grooves that a plurality of negative electrodes (CATHODE) of the LED element D16...D86 of the subordinate of 8 raceway grooves and constant-flow driver 20 are inner is connected, between terminal SO1...SO8 and earthing potential are set in the constant current of the actuator unit 21...28 of 8 raceway grooves of constant-flow driver 20, is connected constant current setting resistance R s respectively.

(constant-flow driver)

The actuator unit 21 of constant-flow driver 20 is made up of differential amplifier 211, N-channel MOS transistor 212 and abnormality detection comparer 213; Non-inverting input to differential amplifier 211 is supplied with reference voltage Vref, and the lead-out terminal of differential amplifier 211 is connected with the gate terminal of N-channel MOS transistor 212.The source terminal of N-channel MOS transistor 212 is connected with the end that resistance R s is set in constant current with the reversed input terminal of differential amplifier 211; The other end that resistance R s is set in constant current is connected with earthing potential, and the drain terminal of N-channel MOS transistor 212 is connected via the negative electrode of the LED element D16 of the subordinate of the lead-out terminal OUT1 of actuator unit 21 and first raceway groove.

Because the differential amplifier 211 of the actuator unit 21 that comprises in the constant-flow driver 20 and N-channel MOS transistor 212 are as voltage follower work; So reference voltage Vref is supplied with at the two ends through set resistance R s to constant current, sets the first raceway groove LED drive current I of the LED element D16...D16 that flows into first raceway groove _LED<1>Current value.The luminosity of the D11...D16 of the White LED array in the time of thus, can being 100% dutycycle to the high value of light modulation pulse width modulation drive signal DPWMO < 1>is set at desirable value.

Non-inverting input of the abnormality detection comparer 213 of the actuator unit 21 that in constant-flow driver 20, comprises is supplied with the voltage of the gate terminal of N-channel MOS transistor 212, supplies with abnormality detection judgment standard voltage V to reversed input terminal _LIMSupply with the abnormality detection judgement signal LIMIT < 1>of the lead-out terminal of abnormality detection comparer 213 to the counter controls portion 32 of logical block 30.

The actuator unit 22 (not shown) of other raceway groove that constant-flow driver 20 is inner ... actuator unit 28 also all with actuator unit 21 fully likewise; Comprise the abnormality detection comparer; Also comprise differential amplifier and N-channel MOS transistor, so set other the second raceway groove LED drive current I as voltage follower work _LED<2>(not shown) ... the 8th raceway groove LED drive current I _LED<8>Current value.Therefore, actuator unit 22 (not shown) ... the abnormality detection of actuator unit 28 is judged signal LIMIT < 2>(not shown) ... LIMIT < 8>also judges that with abnormality detection signal LIMIT < 1>fully likewise is supplied to the counter controls portion 32 of logical block 30.

(logical block)

Logical block 30 comprises light adjusting controller 31, counter controls portion 32 and up-down counter 33.

Synchronously supply with 1 bit serial brightness adjustment control data with light modulation clock DPWMCLK to the light adjusting controller 31 of logical block 30.Light adjusting controller 31 is supplied with light modulation pulse width modulation drive signal DPWMO < 1>to the actuator unit 21...28 of constant-flow driver 20 ... < 8>in response to the brightness adjustment control data.Light modulation pulse width modulation drive signal DPWMO < 1>... each drive signal < 8>can be utilized during the high value and the luminosity of recently adjusting LED between low periods.And then, from the light modulation pulse width modulation drive signal DPWMO < 1>of light adjusting controller 31 generations ... < 8>also be supplied to counter controls portion 32.

And then, in response to the light modulation pulse width modulation drive signal DPWMO of high value<1>, actuator unit 21 differential amplifier 211 and N channel power MOS transistor 212 be activated, can drive the first raceway groove LED drive current I of the LED element D11...D16 of first raceway groove _LED<1>The actuator unit 22 (not shown) of other raceway groove of constant-flow driver 20 inside ... actuator unit 28 is also all same fully with actuator unit 21; Light modulation pulse width modulation drive signal DPWMO < 2>in response to the high value ... < 8 >; Each differential amplifier of actuator unit 22...28 is activated with each N-channel MOS transistor, can drive the LED drive current of each raceway groove.

Counter controls portion 32 is in response to the light modulation pulse width modulation drive signal DPWMO < 1>that supplies with from light adjusting controller 31 ... < 8>and from the abnormality detection that the actuator unit 21...28 of constant-flow driver 20 supplies with judge signal LIMIT < 1>... LIMIT < 8>generates the rising signals UP and the dropping signal DOWN that supply with to up-down counter 33.

Up-down counter 33 makes 7 count value increase (+1) in response to 1 the rising signals UP that supplies with from counter controls portion 32; On the other hand, up-down counter 33, in response to 1 the dropping signal DOWN that supplies with from counter controls portion 32, the count value that makes 7 reduces (1).

(reference voltage generates the D/A transducer)

Reference voltage generates D/A transducer 50 in response to 7 the count value of in up-down counter 33, preserving, and carries out to generate reference voltage V _REFThe A/D conversion.

(switching regulaor)

Boost DC-DC converter 10 as switching regulaor work is made up of error amplifier 11 and controller 12.Non-inverting input to error amplifier 11 is supplied with the reference voltage V that generates 50 generations of D/A transducer from reference voltage _REF, supply with the feedback electricity V that generates from feedback circuit 6 to the reversed input terminal of error amplifier 11 _FBIn addition, through two divider resistance R1 that utilize feedback circuit 6, the output DC electricity V that R2 generates the negative electrode from commutation diode 4 _OUTDividing potential drop and generate feedback voltage V _FB

The switching regulaor that constitutes by boost DC-DC converter 10, inductor 2, N channel power MOS transistor 3, commutation diode 4 and smmothing capacitor 5 through the connection that makes power MOS transistor 3 during and between off period of power MOS transistor 3 repeatedly, carry out from the negative electrode of commutation diode 4 and generate output DC electricity V _OUTPulse-length modulation (PWM) action.

If the inductance of inductor 2 is L, the time is t, then during the connection of power MOS transistor 3, via inductor 2 and power MOS transistor 3 from input DC electricity V _INThe electric current that flows and to provide to earthing potential by following formula:

I _ON=V _INT/L formula (5)

I _OFF=(V _IN-V _OUT) t/L formula (6)

If during the connection of power MOS transistor 3 be T _ON, power MOS transistor 3 off period between be T _OFF, then the boundary during two must be equated with the electric current that is provided by formula (6) by the electric current that formula (5) provides.Therefore, obtain following formula.

V _INT _ON/ L=(V _IN-V _OUT) T _OFF/ L formula (7)

If launch this formula (7), then obtain the relation of following formula.

V _OUT=(1+ (T _ON/ T _OFF)) V _INFormula (8)

This formula (8) illustrates, and the switching regulaor generation that is made up of boost DC-DC converter 10, inductor 2, N channel power MOS transistor 3, commutation diode 4 and smmothing capacitor 5 has than defeated dc voltage V _INThe output dc voltage V of the big voltage of voltage _OUT

On the other hand, owing to supply with two divider resistance R1 utilizing feedback circuit 6, R2 output dc voltage V to the reversed input terminal of error amplifier 11 _OUTDividing potential drop and the feedback voltage V that generates _FB, supply with the reference voltage V that generates 50 generations of D/A transducer from reference voltage to non-inverting input of error amplifier 11 _REF So error amplifier 11 work are so that feedback voltage V _FBMagnitude of voltage and reference voltage V _REFMagnitude of voltage consistent, thereby generate output dc voltage V _OUTThat is, controller 12 utilize between rising stage of triangular waveform of pulse-length modulation (PWM) and the ratio between decrement phase confirm to connect during T _ONAnd T between the off period _OFFRatio so that these two magnitude of voltage unanimities.

Therefore, that kind shown in the image pattern 2 when DC-DC transducer 10 is step-up DCs-DC transducer, generates and has than input dc voltage V _INThe output dc voltage V of the big voltage of voltage _OUTWhen DC-DC transducer 10 was another routine buck DC-DC converter, generation had than defeated dc voltage V _INThe output dc voltage V of the little voltage of voltage _OUTWhen DC-DC transducer 10 was buck-boost type DC-DC transducer, generation had than defeated dc voltage V _INThe output dc voltage V of the big voltage of voltage _OUTAnd have than defeated dc voltage V _INThe output dc voltage V of the little voltage of voltage _OUT

(work of SIC (semiconductor integrated circuit))

1 controlling and driving SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2; If through preset time, then carry out output dc voltage V termly at the driving duration of work of the D11...D16～D81...D86 of the White LED array that is formed by connecting a plurality of White LED elements _OUTCalibration operation.

Before this calibration operation, reference voltage generates D/A transducer 50 in response to 7 the count value of in the up-down counter 33 of logical block 30, preserving in advance, generates reference voltage V _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of boost DC-DC converter 10 passes through in response to reference voltage V _REFConfirm (T during the connection between rising stage of triangular waveform of pulse-length modulation _ON) and decrement phase between (T between the off period _OFF) ratio, set output dc voltage V _OUTMagnitude of voltage.

At this output dc voltage V _OUTThe imposing a condition of magnitude of voltage under, the D11...D16～D81...D86 of White LED array is driven the first raceway groove LED drive current I by SIC (semiconductor integrated circuit) 1 _LED<1>... the 8th raceway groove LED drive current I _LED<8>Each current value be configured to normal constant current value, the D11...D16～D81...D86 of White LED array all is configured to normal luminosity.

But, at the positive dirction voltage V that makes the PN junction of a plurality of LED element D11...D16～D81...D86 because of temperature decline extremely _FWhen extremely increasing, the first raceway groove LED drive current I _LED<1>... the 8th raceway groove LED drive current I _LED<8>The initial normal constant current value of each current value ratio low, so the voltage drop that constant current is set between resistance R s two ends significantly reduces than reference voltage Vref.If like this, then the differential amplifier 211 of actuator unit 21 is to the output voltage of the extremely high value of the grid supply of N channel power MOS transistor 212, to compensate the first raceway groove LED drive current I _LED<1>Reduce.The actuator unit 22 (not shown) of other raceway groove that constant-flow driver 20 is inner ... actuator unit 28 also all with actuator unit 21 fully likewise, the second raceway groove LED drive current I _LED<2>... the 8th raceway groove LED drive current I _LED<8>Each current value also the normal constant current value than initial is low; Therefore each differential amplifier of the actuator unit 22...28 of other raceway groove is to the output voltage of the high value of the transistorized grid supply of each N channel power MOS, to compensate reducing of each raceway groove LED drive current.

Under these circumstances, the abnormality detection comparer 213 of the actuator unit 21 of constant-flow driver 20 detects: to the gate drive voltage and the abnormality detection judgment standard voltage V that supplies with to reversed input terminal of the sub N-channel MOS transistor of supplying with 212 of non-inverting input _LIMCompare extremely high.Its result, abnormality detection comparer 213 generates the abnormality detection of high value and judges signal LIMIT < 1 >, supplies to the counter controls portion 32 of logical block 30.The actuator unit 22... actuator unit 28 of other raceway groove that constant-flow driver 20 is inner also all with actuator unit 21 fully likewise; The abnormality detection comparer generates the abnormality detection of high value and judges signal LIMIT < 2>... < 8 >, supply to the counter controls portion 32 of logical block 30.

Owing to judge signal LIMIT < 1>... when the some signals < 8>are the high value in a plurality of abnormality detection; The counter controls portion 32 of logical block 30 generates 1 rising signals UP and supplies to up-down counter 33, so up-down counter 33 makes 7 count value increase (+1) in response to 1 rising signals UP.Therefore, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 upgrade count value, generated than increased in the past the reference voltage V of predetermined voltage swing _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of rising.

If because output dc voltage V _OUTRising, whole raceway groove LED drive current I _LED<1>... I _LED<8>Each current value return to initial normal constant current value, the voltage drop that then whole constant current is set between resistance R s two ends returns to reference voltage Vref.If like this; Then judge signal LIMIT < 1>... < 8>all become low value in response to a plurality of abnormality detection; The counter controls portion 32 of logical block 30 neither generates rising signals UP and does not also generate dropping signal DOWN; So do not upgrade 7 the count value that is kept in the up-down counter 33, before carrying out next calibration operation, be kept at it in the up-down counter 33 always.

At whole raceway groove LED drive current I _LED<1>... I _LED<8>Each current value not because output dc voltage V _OUTRising and when returning to initial normal constant current value, because a plurality of abnormality detection are judged signal LIMIT<1>...<8>In some signals still be low value, so counter controls portion 32 further generates 1 rising signals UP and supplies to up-down counter 33.Therefore, because up-down counter 33 further makes 7 count value increase (+1), reference voltage generates the reference voltage V that D/A transducer 50 generates has further increased predetermined voltage swing _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Its result, the controller 12 of boost DC-DC converter 10 is in response to the reference voltage V that has further increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of further rising.That is, judge signal LIMIT in a plurality of abnormality detection<1>...<8>All become before the low value, carry out the increase action of up-down counter 33, the reference voltage V that reference voltage generates D/A transducer 50 repeatedly _REFVoltage increase and the output dc voltage V of boost DC-DC converter 10 _OUTVoltage increase.

In 1 controlling and driving SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2, at the initial input dc voltage V that supplies with as working power voltage _INPower connection the time initialization sequence in output dc voltage V _OUTCalibration operation in, in response to the predetermined initial value of 7 count value in the up-down counter that is kept at logical block 30 33, reference voltage generates the reference voltage V that D/A transducer 50 generates initial values _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of boost DC-DC converter 10 is in response to the reference voltage V of initial value _REF, generate the output dc voltage V of initial value _OUTThe work of magnitude of voltage.In addition, the power-on-reset signal of counter controls portion 32 during in response to power connection for example, 7 the initial value of preserving in the nonvolatile memory that waits counter controls portion 32 inner ROM (read-only memory)s (ROM) of being scheduled to is kept in the up-down counter 33.In addition; Also can in the nonvolatile memory of the inner ROM (read-only memory) of SIC (semiconductor integrated circuit) 1, flash memory etc., preserve 7 predetermined initial value; Power-on-reset signal during in response to power connection; 7 predetermined initial value is read by counter controls portion 32 from nonvolatile memory, be kept in the up-down counter 33.

Generating the output dc voltage V of this initial value _OUTThe situation of magnitude of voltage under, judge signal LIMIT in a plurality of abnormality detection<1>...<8>When all being low value, because the counter controls portion of logical block 30 32 generates 1 dropping signal DOWN and supply to up-down counter 33, so up-down counter 33 makes 7 count value reduce (1) in response to 1 dropping signal DOWN.Its result, reference voltage generates D/A transducer 50 and upgrades count value in response to-1 of up-down counter 33, has generated than has reduced in the past the reference voltage V of predetermined voltage swing _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V of boosting that has reduced _REF, make the output dc voltage V that boosts _OUTThe work that reduces of magnitude of voltage.

Even at output dc voltage V _OUTDescend whole raceway groove LED drive current I _LED<1>... I _LED<8>Each current value when also keeping normal constant current value, because a plurality of abnormality detection are judged signal LIMIT<1>...<8>All be low value, thus counter controls portion 32 further generate 1 dropping signal DOWN and supply to up-down counter 33, so up-down counter 33 further makes 7 count value further reduce (1) in response to 1 dropping signal DOWN.Therefore, reference voltage generates second-1 renewal count value of D/A transducer 50 in response to up-down counter 33, generates the reference voltage V that has further reduced predetermined voltage swing _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has further reduced _REF, make output dc voltage V _OUTThe work that further reduces of magnitude of voltage.

Because output dc voltage V _OUTFurther reduction, a plurality of abnormality detection are judged signal LIMIT<1>...<8>In some signals when becoming high value; Counter controls portion 32 generates as the rising signals UP of the final setting signal of count value and supplies to up-down counter 33; So up-down counter 33 makes 7 count value increase (+1) through the rising signals UP in response to the final setting signal of count value, thereby resets into output dc voltage V to count value _OUTCount value before just having reduced.Its result, reference voltage generates the recovery count value of D/A transducer 50 in response to up-down counter 33, reference voltage V _REFReset into output dc voltage V _OUTJust reduce magnitude of voltage before, and supplied to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, controller 12 is in response to restoring reference voltage V _REF, make output dc voltage V _OUTThereby magnitude of voltage rise and to reset into the work of the magnitude of voltage before just reducing.Its result through the final action of setting of this count value, makes whole raceway groove LED drive current I _LED<1>... I _LED<8>Each current value return to initial normal constant current value.That is, through calibration output dc voltage V _OUTMagnitude of voltage, can supply with steady current to the White LED array, can keep constant to brightness.

In addition, since 10 in DC-DC transducer reference voltage V _REFAnd feedback voltage V _FBThese two inputs generate output dc voltage V as benchmark _OUTSo system is stable always, is difficult to take place unsettled work.

Though in Fig. 3, be not shown specifically; But in calibration operation also with common duration of work fully likewise, a plurality of light modulation pulse width modulation drive signal DPWMO < 1>that supply with to the actuator unit 21...28 of constant-flow driver 20 ... be to disperse type of drive < 8 >.

That is, the second drive signal DPWMO < 2>from low value to moment that the high value changes than the first drive signal DPWMO < 1>from the moment delay scheduled time of low value to the variation of high value.The 3rd drive signal DPWMO < 3>from low value to moment that the high value changes than the second drive signal DPWMO < 2>from the moment delay scheduled time of low value to the variation of high value.The moving signals DP WMO < 4>of 4 wheel driven from low value to moment that the high value changes than the 3rd drive signal DPWMO < 3>from the moment delay scheduled time of low value to the variation of high value.The 5th drive signal DPWMO < 5>from low value to moment that the high value changes than the moving signals DP WMO of 4 wheel driven < 4>from the moment delay scheduled time of low value to the variation of high value.The 6th drive signal DPWMO < 6>from low value to moment that the high value changes than the 5th drive signal DPWMO < 5>from the moment delay scheduled time of low value to the variation of high value.The 7th drive signal DPWMO < 7>from low value to moment that the high value changes than the 6th drive signal DPWMO < 6>from the moment delay scheduled time of low value to the variation of high value.The 8th drive signal DPWMO < 8>from low value to moment that the high value changes than the 7th drive signal DPWMO < 7>from the moment delay scheduled time of low value to the variation of high value.Its result is through making whole raceway groove LED drive current I _LED<1>... I _LED<8>Whole current values sharply increase in the roughly the same moment, can alleviate the output dc voltage V of DC-DC transducer 10 _OUTThe problem that reduces of magnitude of voltage moment.

T1 is to the SIC (semiconductor integrated circuit) 1 initial input dc voltage V that supplies with as working power voltage between the first phase of Fig. 3 _INPower connection the time the output dc voltage V of initialization sequence _OUTCalibration operation initial during, set the count value of up-down counter 33 for predetermined initial value 3Fh.Should be set at the roughly middle input digit value that reference voltage generates the D/A conversion dynamic range of D/A transducer 50 by predetermined initial value 3Fh.Therefore, in response to 7 the counting initial value 3Fh that in up-down counter 33, preserves, reference voltage generates the reference voltage V that D/A transducer 50 generates initial value _REF, supply with to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of boost DC-DC converter 10 is in response to the reference voltage V of initial value _REF, generate the output dc voltage V of initial value _OUTThe work of magnitude of voltage.

Between the first phase of Fig. 3 among the T1; Because a plurality of abnormality detection are judged signal LIMIT < 1>... < 8>all be low value; So the counter controls portion 32 of logical block 30 further generates 1 dropping signal DOWN and supplies to up-down counter 33, up-down counter 33 makes count value reduce (1) in response to 1 dropping signal DOWN in the second phase of Fig. 3 T2.

Its result, in the second phase of Fig. 3 T2, reference voltage generates D/A transducer 50 and upgrades count value 3Eh in response to-1 of up-down counter 33, generates the reference voltage V than initial value _REFReduced the reference voltage V of predetermined voltage _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has reduced _REF, make output dc voltage V _OUTThe work that reduces of magnitude of voltage.And, a plurality of light modulation pulse width modulation drive signal DPWMO < 1>... changing from the second phase T2 of Fig. 3 to the level value of high value from low value of dispersing mode < 8>begins.Therefore, the actuator unit 21 beginnings first raceway groove LED drive current I of first raceway groove in the second phase of Fig. 3 T2 _LED<1>Driving.

In the second phase of Fig. 3 T2, even because output dc voltage V _OUTDescend the first raceway groove LED drive current I _LED<1>Current value when also keeping normal constant current value, the abnormality detection of first raceway groove is judged signal LIMIT<1>Be low value, thus counter controls portion 32 further generate 1 dropping signal DOWN and supply to up-down counter 33, so up-down counter 33 further makes count value further reduce (1) in response to 1 dropping signal DOWN.

Its result, among the T3, reference voltage generates D/A transducer 50 and upgrades count value 3Dh in response to-1 of up-down counter 33, generates the reference voltage V that has reduced predetermined voltage swing between the third phase of Fig. 3 _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the boost pressure controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has further reduced _REF, make output dc voltage V _OUTThe work that further reduces of magnitude of voltage.

Between the third phase of Fig. 3 among the T3, because output dc voltage V _OUTReduce, so the first raceway groove LED drive current I _LED<1>The initial normal constant current value of current value ratio low.Therefore, the abnormality detection that generates high value from the lead-out terminal of the abnormality detection comparer 213 of the actuator unit 21 of constant-flow driver 20 is judged signal LIMIT < 1 >, and supplies to the counter controls portion 32 of logical block 30.Its result; Counter controls portion 32 generates 1 rising signals UP and supplies to up-down counter 33; Up-down counter 33 makes count value increase (+1) and resets into and just upgrade renewal count value 3Eh before in response to 1 rising signals UP among the T4 between the fourth phase of Fig. 3.

Its result, between the fourth phase of Fig. 3 among the T4, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 restore count value 3Eh, generate reference voltage V than T3 between the third phase _REFIncreased the reference voltage V before just the upgrading of predetermined voltage _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V before just upgrading _REF, make output dc voltage V _OUTMagnitude of voltage rise and reset into the work of the magnitude of voltage before just upgrading.Its result is owing to make first low than the initial normal constant current value raceway groove LED drive current I _LED<1>Current value rise to initial normal constant current value, so the abnormality detection of first raceway groove is judged signal LIMIT<1>From the high value to low-value variation.Therefore, judge signal LIMIT in response to the abnormality detection of first raceway groove<1>Moment t23 from low value to the high value change so that at moment t34 from of the reciprocal state transition of high value to low-value variation, the counter controls portion 32 of logical block 30 makes expression output dc voltage V _OUTThe low-voltage of finding first of minimum voltage find that signal LOW_FIND changes to the high value from low value.And then counter controls portion 32 finds that in low-voltage signal LOW_FIND is under the state of high value, reads the first light modulation pulse width modulation drive signal DPWMO<1>Keep the abnormality detection of the high value and first raceway groove and judge signal LIMIT<1>Keep the content of low value, be judged as the first raceway groove LED drive current I _LED<1>Current value be normal constant current value, to the relevant output dc voltage V of expression and the actuator unit of first raceway groove 21 _OUTFirst raceway groove inspection end signal CHK_END of the high value that finishes of calibration operation<1>Write high value.

And then, between the fourth phase of Fig. 3 among the T4, at output dc voltage V _OUTMaintain magnitude of voltage before just upgrading during because the second raceway groove LED drive current I _LED<2>... the 7th raceway groove LED drive current I _LED<7>Maintain initial normal constant current value, so judge signal LIMIT from the abnormality detection of second raceway groove<2>Abnormality detection to the 7th raceway groove is judged signal LIMIT<7>All keep low value.

Therefore; The counter controls portion 32 of logical block 30 read among the T4 between the fourth phase of Fig. 3: low-voltage finds that signal LOW_FIND keeps high value; And the pulse width modulation drive signal DPWMO < 2>of second raceway groove ... the pulse width modulation drive signal DPWMO < 7>of the 7th raceway groove keeps high value; And the abnormality detection of second raceway groove judges that signal LIMIT < 2>judges that to the abnormality detection of the 7th raceway groove signal LIMIT < 7>keeps low value, to second raceway groove inspection end signal CHK_END < 2>of low value ... the 7th raceway groove inspection end signal CHK_END < 7>writes high value.

Between the fifth phase of Fig. 3 among the T5, in response to the pulse width modulation drive signal DPWMO of the 8th raceway groove<8>Change actuator unit 28 beginnings the 8th raceway groove LED drive current I of the 8th raceway groove to the high value from low value _LED<8>Driving.But, because the 8th raceway groove LED drive current I _LED<8>The normal constant current value of current value ratio low, so the abnormality detection that generates high value from the lead-out terminal of the abnormality detection comparer of the actuator unit 28 of constant-flow driver 20 is judged signal LIMIT<8>, and supply to the counter controls portion 32 of logical block 30.Therefore, counter controls portion 32 generates 1 rising signals UP and supplies to up-down counter 33, the first half of T5 between the fifth phase of Fig. 3, and up-down counter 33 makes count value increase (+1) in response to 1 rising signals UP and becomes+1 renewal count value 3Fh.

Therefore, the first half of T5 between the fifth phase of Fig. 3, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 upgrade count value 3Fh, generate reference voltage V than T4 between the fourth phase _REFIncreased the reference voltage V of predetermined voltage _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of rising and restoring.

But, although between the fifth phase of Fig. 3 the output dc voltage V of the first half of T5 _OUTMagnitude of voltage rise the 8th raceway groove LED drive current I _LED<8>Current value still low than normal constant current value.Its result, the abnormality detection that generates high value from the lead-out terminal of the abnormality detection comparer of the actuator unit 28 of constant-flow driver 20 is judged signal LIMIT < 8 >, and supplies to the counter controls portion 32 of logical block 30.Therefore, counter controls portion 32 generates 1 rising signals UP and supplies to up-down counter 33, and the latter half of T5 between the fifth phase of Fig. 3, up-down counter 33 make count value increase (+1) and become+1 renewal count value 40h in response to 1 rising signals UP.

Therefore, the latter half of T5 between the fifth phase of Fig. 3, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 upgrade count value 40h, generate reference voltage V than T4 between the fourth phase _REFIncreased the reference voltage V of predetermined voltage _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of rising.

But although the latter half of T5 between the fifth phase of Fig. 3 is output dc voltage V _OUTMagnitude of voltage rise the 8th raceway groove LED drive current I _LED<8>Current value still low than normal constant current value.Its result, the abnormality detection that generates high value from the lead-out terminal of the abnormality detection comparer of the actuator unit 28 of constant-flow driver 20 is judged signal LIMIT < 8 >, and supplies to the counter controls portion 32 of logical block 30.Therefore, counter controls portion 32 generates 1 rising signals UP and also supplies to up-down counter 33, Fig. 3 the 6th during among the T6, up-down counter 33 makes count value increase (+1) and become in response to 1 rising signals UP+1 upgrade count value 41h.

Therefore, Fig. 3 the 6th during among the T6, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 upgrade count value 41h, generate reference voltage V than the latter half of T5 between the fifth phase _REFIncreased the reference voltage V of predetermined voltage _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of rising.

Its result is owing to make the 8th low than initial normal constant current value raceway groove LED drive current I _LED<8>Current value rise and reset into initial normal constant current value, so the abnormality detection of the 8th raceway groove is judged signal LIMIT<8>From the high value to low-value variation.

Therefore, find that in response to low-voltage signal LOW_FIND keeps high value, the pulse width modulation drive signal DPWMO of the 8th raceway groove<8>Keep the abnormality detection of high value and the 8th raceway groove and judge signal LIMIT<8>Become the state of low value, counter controls portion 32 is to the relevant output dc voltage V of expression and the actuator unit of the 8th raceway groove 28 _OUTThe 8th raceway groove inspection end signal CHK_END of the high value that finishes of calibration operation<8>Write high value.

That is, do not exporting raceway groove abnormality detection judgement signal LIMIT<8>During because raceway groove LED drive current I _LED<8>Current value reduce power consumption in normal scope the time, reduce reference voltage V so be controlled to _REF, to reduce output dc voltage V _OUTMagnitude of voltage.In addition, judge signal LIMIT in output raceway groove abnormality detection<8>During, the LED brightness of step-down becomes normal condition in order to make, is controlled to through increasing reference voltage V _REFControl improve output dc voltage V _OUTMagnitude of voltage, as a result of can make raceway groove LED drive current I _LED<8>Current value rise and become normal constant current value.

That kind shown in the image pattern 4 during the driving work Norm_OP of the D11...D16～D81...D86 of the White LED array of preset time, is carried out the output dc voltage V that boosts termly _OUTCalibration operation Cal_OP.In addition, through at the output dc voltage V that boosts _OUTCalibration operation Cal_OP during carry out the output dc voltage V that boosts _OUTVoltage adjustment Vadj, control changeably SIC (semiconductor integrated circuit) 1 constant-flow driver 20 8 raceway grooves actuator unit 21...28 lead-out terminal OUT1...OUT8 output voltage V _ _OUT1... V_ _OUT8

And then, can find out, that kind shown in the image pattern 4, during the driving work Norm_OP of the D11...D16～D81...D86 of White LED array, the semi-conductor chip temperature T of SIC (semiconductor integrated circuit) 1 _CHWhen high temperature changed, through changing the calibration operation Cal_OP that carry out the back to high temperature, output dc voltage V boosted from low temperature _OUTAnd output voltage V _ _OUT1... V_ _OUT8Automatically be adjusted to low magnitude of voltage.

(embodiment 2)

(calibration operation of the output dc voltage that boosts)

In the initial step 500 of Fig. 5, the count value DATA_VREF of up-down counter 33<6:0>Set predetermined initial value 3Fh for, expression output dc voltage V _OUTThe low-voltage of finding first of minimum voltage find that signal LOW_FIND sets low value for, the boost pressure controller 12 of DC-DC transducer 10 is the reference voltage V of initial value _REFSet 1.875V for.

In the step of following 501, counter controls portion 32 roughly reads the abnormality detection from actuator unit 21 of totally 8 raceway grooves concurrently and judges that signal LIMIT < 1>judges the value of each signal of signal LIMIT < 8>to the abnormality detection of actuator unit 28.In reality; Counter controls portion 32 read high value the first drive signal DPWMO < 1>during the value of abnormality detection judgement signal LIMIT < 1>of actuator unit 21; Read then high value the second drive signal DPWMO < 2>during the abnormality detection of actuator unit 22 judge the value of signal LIMIT < 2 >, below the last high value of likewise reading the 8th drive signal DPWMO < 8>during the value of abnormality detection judgement signal LIMIT < 8>of actuator unit 28.

In the step of following 502, the 32 inspection expression output dc voltage V of counter controls portion _OUTThe low-voltage of finding first of minimum voltage find the magnitude of voltage of signal LOW_FIND.Find that in low-voltage signal LOW_FIND transfers to step 503 when being low value " 0 "; , low-voltage transfers to step 508 when finding signal LOW_FIND for high value " 1 ".

In step 503; The abnormality detection of counter controls portion 32 inspections, 8 raceway grooves is judged signal LIMIT < 1>... whole value < 8 >; Transfer to the reducing of step 504 (1) when it all is low value " 0 " (no abnormal) and handle, its some increase (+1) processing of transferring to step 505 during for high value " 1 " (having unusual).That is when, all being low value " 0 " (no abnormal) because output dc voltage V _OUTHave more than needed, so in order to reduce output dc voltage V _OUT, the count value DATA_VREF of up-down counter 33<6:0>Value reduce (1), and some during for high value " 1 " (having unusual) owing to output dc voltage V _OUTSo deficiency is in order to increase output dc voltage V _OUT, the count value DATA_VREF of up-down counter 33<6:0>Value increase (+1).

Reducing in (1) processing of step 504, up-down counter 33 is in response to 1 the dropping signal DOWN that supplies with from counter controls portion 32, and the count value that makes 7 reduces (1).

In the increase (+1) of step 505 was handled, up-down counter 33 made 7 count value increase (+1) in response to 1 the rising signals UP that supplies with from counter controls portion 32.

And then in the step 506 that carry out step 505 back, counter controls portion 32 makes expression output dc voltage V _OUTThe low-voltage of finding first of minimum voltage find that signal LOW_FIND changes to the high value from low value.

And then, handle the back or in the step 507 that carry out step 506 back the reducing of step 504 (1), in response to the increase (+1) of preserving in the up-down counter 33 or reduce (1) count value, reference voltage generates D/A transducer 50 and generates reference voltage V _REFIn addition, in response to the renewal count value of up-down counter 33, for the work of the controller 12 through DC-DC transducer 10 makes output dc voltage V _OUTThe variation of magnitude of voltage finish, need of short duration transit time.

Owing in step 507, generated the output dc voltage V of the magnitude of voltage that has upgraded _OUTAfter, return initial step 501 and handle, so reading the abnormality detection of 8 raceway grooves once more, counter controls portion 32 judges signal LIMIT<1>...<8>, counter control part 32 is checked expression output dc voltage V once more in step 502 then _OUTThe low-voltage of finding first of minimum voltage find the magnitude of voltage of signal LOW_FIND.

In this step 502, because low-voltage finds that signal LOW_FIND changes to the high value from low value in the former step 506, so find that signal LOW_FIND is judged as high value " 1 ", transfers to next step 508 to low-voltage.

In step 508, counter controls portion 32 checks that once more the abnormality detection of 8 raceway grooves judges signal LIMIT < 1>... < 8>whole value.The certain result who reexamines as step 508 transfers to step 510 when all being low value " 0 " (no abnormal).In contrast, as the outer result of the expectation that reexamines of step 508, some increase (+1) processing of transferring to step 509 during for high value " 1 " (having unusual).

Whether 32 checkings of counter control part check end signal CHK_END < 1>to the raceway groove of whole 8 raceway grooves in step 510 ... < 8>write high value " 1 ".When the checking result is " denying ", returns initial step 501 and handle; When the checking result was " good ", counter controls portion 32 set output dc voltage V in step 511 _OUTCalibration operation in the count value DATA_VREF of up-down counter 33<6:0>Final setting value.The major part of the final setting value of the count value DATA_VREF < 6:0>that sets in this step 511 is the count value after the increase (+1) of step 505 is handled, and the part of exception is the count value after the increase of step 509 (+1) is handled.

Count value DATA_VREF in step 511<6:0>Final setting handle after, reference voltage generates D/A transducer 50 and generates and the corresponding reference voltage V of final setting count value in step 512 _REFAnd then in step 512, the controller 12 of DC-DC transducer 10 uses this reference voltage V _REFSet output dc voltage V _OUTThe action of magnitude of voltage.And then, in step 512, supply with this output dc voltage V at a plurality of anodes to the higher level's of 8 raceway grooves LED element D11...D81 _OUTState under, the lead-out terminal OUT1...OUT8 of the actuator unit 21...28 of 8 raceway grooves that constant-flow driver 20 is inner drives a plurality of negative electrodes of LED element D16...D86 of the subordinate of 8 raceway grooves.Its result is owing to have the first raceway groove LED drive current I of normal constant current value _LED<1>... the 8th raceway groove LED drive current I _LED<8>Flow through the White LED array, so can all set the whole LED element D11...D16～D81...D86 that comprises in the White LED array for normal luminosity.In addition; LED element D11...D16～D81...D86 that comprises in the White LED array in the step 512 and above-mentioned embodiment of the present invention 1 are with a plurality of light modulation pulse width modulation drive signal DPWMO < 1>fully likewise ... < 8>dispersion drives.

If for the driving duration of work of the D11...D16～D81...D86 of the White LED array in step 512, in step 513,, then carry out output dc voltage V termly through preset time _OUTCalibration operation, transfer in the step 514 and handle.In step 514, counter controls portion 32 is the raceway groove of 8 raceway grooves inspection end signal CHK_END < 1>... CHK_END < 8>finds that with low-voltage signal LOW_FIND zero clearing becomes low value.After the processing of step 514, handle owing to return initial step 501, so begin output dc voltage V once more _OUTCalibration operation.

As above explanation, 2 the output dc voltage V according to the embodiment of the present invention that Fig. 5 explained _OUTThe treatment scheme of calibration operation in step 502, step 503, step 504 and step 507, all reducing output dc voltage V one by one in the normal scopes of raceway groove _OUTEven raceway groove detects when unusual also the setting of minimum power consumption condition that increase (+1) through the count value in the step 505 realizes the regular event of whole raceway grooves in step 503 then.In addition; In the treatment scheme of the calibration operation of Fig. 5; Behind the minimum power consumption condition enactment of whole regular events of raceway grooves; If taken place in step 508, to detect outside the unusual expectation as a result the time, realize the setting once more of minimum power consumption condition of the regular event of whole raceway grooves through the appending of the count value in the step 509 (+1).

(embodiment 3)

(according to the formation of the SIC (semiconductor integrated circuit) of embodiment 3)

3 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 6 is following with the difference of 1 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2.

Promptly; To the reversed input terminal and non-inverting input of the abnormality detection comparer 213 of the actuator unit 21 of the constant-flow driver 20 of 3 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 6, supply with the voltage (voltage of terminal SO1 is set in the constant current of actuator unit 21) and the abnormality detection judgment standard voltage V of the source terminal of N-channel MOS transistor 212 respectively _LIMIn addition, abnormality detection judgment standard voltage V _LIMMagnitude of voltage set for example about 1/2 the magnitude of voltage of reference voltage Vref for.In addition, the actuator unit 22 (not shown) of other raceway groove of constant-flow driver 20 inside ... actuator unit 28 also all fully likewise constitutes with actuator unit 21.

Promptly; In 3 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 6 also be, because of temperature extremely descends, the positive dirction voltage V of the PN junction of former thereby a plurality of LED element D11...D16～D81...D86 of the characteristic deviation of the extreme of LED element etc. _FWhen extremely increasing, the first raceway groove LED drive current I _LED<1>... the 8th raceway groove LED drive current I _LED<8>The initial normal constant current value of each current value ratio low.Therefore, the voltage drop between constant current setting resistance R s two ends significantly reduces than reference voltage Vref.

Under these circumstances; In 3 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 6, the abnormality detection judgment standard voltage V of the voltage of the source terminal of the N-channel MOS transistor 212 of the reversed input terminal of the abnormality detection comparer 213 of the actuator unit 21 of constant-flow driver 20 and non-inverting input _LIMCompare remarkable reduction.Its result, abnormality detection comparer 213 generates the abnormality detection of high value and judges signal LIMIT < 1 >, and supplies to the counter controls portion 32 of logical block 30.The actuator unit 22... actuator unit 28 of other raceway groove of constant-flow driver 20 inside; Also all with actuator unit 21 fully likewise; The abnormality detection comparer generates the abnormality detection of high value and judges signal LIMIT < 2>... < 8 >, and supplies to the counter controls portion 32 of logical block 30.

Owing to judge signal LIMIT < 1>... when the some signals < 8>are the high value in a plurality of abnormality detection; The counter controls portion 32 of logical block 30 generates 1 rising signals UP and supplies to up-down counter 33, so up-down counter 33 makes 7 count value increase (+1) in response to 1 rising signals UP.Therefore, reference voltage generate D/A transducer 50 in response to up-down counter 33+1 upgrade count value, generated than increased in the past the reference voltage V of predetermined voltage swing _REF, and supply to non-inverting input of the error amplifier 11 of boost DC-DC converter 10.Therefore, the boost pressure controller 12 of DC-DC transducer 10 is in response to the reference voltage V that has increased _REF, make output dc voltage V _OUTThe magnitude of voltage work of rising.

As above explanation, 3 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 6 can be realized the holding function same with shown in Figure 21 SIC (semiconductor integrated circuit) according to the embodiment of the present invention 1.

(embodiment 4)

(according to the formation of the SIC (semiconductor integrated circuit) of embodiment 4)

4 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 7 is following with the difference of 1 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2.

Promptly; In the DC-DC transducer 10 of 4 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 7; Through being connected P channel MOS transistor 7, schottky diode 4, inductor 2 and smmothing capacitor 5, constitute buck DC-DC converter to DC-DC transducer 10 to compare the connection status that has changed with Fig. 2.

Therefore, input dc voltage V shown in Figure 7 _INWhen being bigger magnitude of voltage, buck DC-DC converter 10 generates to have than defeated dc voltage V _INThe output dc voltage V of little voltage _OUT

That is, that kind shown in the image pattern 7, input dc voltage V _INBe connected with the source terminal of P channel MOS transistor 7, the drain terminal of P channel MOS transistor 7 is connected with an end of inductor 2 and the negative electrode of schottky diode 4.The anode of schottky diode 4 is connected with earthing potential, and the other end of inductor 2 is connected with a plurality of anodes of the higher level's of feedback circuit 6 and smmothing capacitor 5,8 raceway grooves LED element D11...D81.

If the inductance of inductor 2 is L, the time is t, then during the connection of P channel MOS transistor 7, via power MOS transistor 7 and inductor 2 from input dc voltage V _INTo output dc voltage V _OUTThe electric current that flows and provide by following formula:

I _ON=(V _IN-V _OUT) t/L formula (9)

Between the off period of the power MOS transistor 7 after during connecting, via commutation diode 4 with inductor 2 from earthing potential to output dc voltage V _OUTThe electric current that flows and provide by following formula:

I _OFF=V _OUTT/L formula (10)

If during the connection of power MOS transistor 7 be T _ON, power MOS transistor 7 off period between be T _OFF, then the boundary during two must be equated with the electric current that is provided by formula (10) by the electric current that formula (9) provides.Therefore, obtain following formula.

(V _IN-V _OUT) T _ON/ L=V _OUTT _OFF/ L formula (11)

If launch this formula (11) then obtain the relation of following formula.

V _OUT=V _INT _ON/ (T _ON+ T _OFF) formula (12)

This formula (12) illustrates, and the switching regulaor generation that is made up of boost DC-DC converter 10, inductor 2, P channel power MOS transistor 7, commutation diode 4 and smmothing capacitor 5 has than defeated dc voltage V _INThe output dc voltage V of the little voltage of voltage _OUT

On the other hand, owing to supply with two divider resistance R1 utilizing feedback circuit 6, R2 output dc voltage V to the reversed input terminal of error amplifier 11 _OUTDividing potential drop and the feedback voltage V that generates _FB, supply with the reference voltage V that generates 50 generations of D/A transducer from reference voltage to non-inverting input of error amplifier 11 _REF So error amplifier 11 is worked and is generated output dc voltage V _OUTSo that feedback voltage V _FBThe magnitude of voltage and the reference voltage V of boosting _REFMagnitude of voltage consistent.That is, controller 12 utilize between rising stage of triangular waveform of pulse-length modulation (PWM) and the ratio between decrement phase confirm to connect during T _ONAnd T between the off period _OFFRatio so that these two magnitude of voltage unanimities.

(embodiment 5)

(according to the formation of the SIC (semiconductor integrated circuit) of embodiment 5)

5 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 8 is following with the difference of 4 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 7.

That is, in 5 switching regulaor according to the embodiment of the present invention shown in Figure 8, append N channel power MOS transistor 3 and schottky diode 8.Promptly; The other end of the drain terminal of power MOS transistor 3 and inductor 2 is connected with the anode of feedback circuit 6 with schottky diode 8; The source terminal of power MOS transistor 3 is connected with earthing potential, and the gate terminal of power MOS transistor 3 is with controller 12 controls of buck DC-DC transducer 10.The anode of schottky diode 8 is connected with a plurality of anodes of the higher level's of smmothing capacitor 5 and 8 raceway grooves LED element D11...D81.

(mode of operation of boosting)

Use the switching regulaor of 5 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 8; Controller 12 through with buck DC-DC transducer 10 is controlled to P channel power MOS transistor 7 state of connection always and control is connected/ended to N channel power MOS transistor 3; With 1 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 2 likewise, have than input dc voltage V as generation _INThe output dc voltage V of big voltage _OUTThe work of step-up DC-DC transducer.

(step-down mode of operation)

The switching regulaor that uses 5 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 8 is through be controlled to N channel power MOS transistor 3 state that ends and control is connected/ended to P channel MOS transistor 7 with the controller 12 of buck DC-DC transducer 10 always; With 4 SIC (semiconductor integrated circuit) 1 according to the embodiment of the present invention shown in Figure 7 likewise, have than input dc voltage V as generation _INThe output dc voltage V of little voltage _OUTBuck DC-DC converter work.

More than the invention accomplished based on the specifically clear inventor of various embodiments, but obviously, the invention is not restricted to this, under the prerequisite that does not break away from its main inventive concept, can make various changes.

In above-mentioned embodiment of the present invention; Be the initial value of the count value of up-down counter 33 be set in reference voltage generate D/A transducer 50 the D/A conversion dynamic range roughly in the middle of the mode of input digit value; Be only also not detect to reduce the input digit value when unusual one by one at a raceway groove; Make when unusual the input digit value increase (+1) detecting, set the mode of the count value of up-down counter 33.But; The present invention is not limited to this mode, from the maximal value of dynamic range or high value beginning, does not only also detect at a raceway groove and reduces the input digit value when unusual one by one; Make when unusual the input digit value increase (+1) detecting, thereby set the mode of the count value of up-down counter 33; Or begin from the minimum value or the low value of dynamic range, increase the input digit value one by one, up to whole raceway grooves by the normal mode that detects in, also can be suitable for the present invention.

And, also can be replaced as npn bipolar transistor to the N-channel MOS transistor 212 that comprises in the actuator unit 21 of the constant-flow driver 20 of the SIC (semiconductor integrated circuit) 1 of Fig. 2, Fig. 6.

And, realize also can being suitable for the present invention in the white luminous three-color LED mode at the raceway groove of these three systems of raceway groove of the raceway groove of the raceway groove (string) through the parallel drive red light emitting diodes, green LED and blue LED.

And, through applying voltage and inject electronics and hole respectively, make injected electrons and hole respectively through electron supplying layer and hole transporting layer to negative electrode and anode, in luminescent layer, combine and in the luminous organic EL luminous element, also can be suitable for the present invention.

Claims

1. SIC (semiconductor integrated circuit), a plurality of raceway grooves that can the parallel drive light-emitting device array is characterized in that:

Above-mentioned SIC (semiconductor integrated circuit) comprises DC-DC transducer, current driver, logical block and D/A transducer;

Above-mentioned DC-DC transducer can be supplied with jointly to a plurality of ends of above-mentioned a plurality of raceway grooves of above-mentioned light-emitting device array and boost the input dc voltage or step-down and the output dc voltage that generates;

Above-mentioned current driver has a plurality of actuator units of a plurality of other ends of above-mentioned a plurality of raceway grooves that can drive above-mentioned light-emitting device array;

Each actuator unit of above-mentioned a plurality of actuator units comprises: drive above-mentioned light-emitting device array each raceway groove each other end driving transistors with can detect the unusual detecting device of the drive current of above-mentioned driving transistors;

A plurality of detection signals that above-mentioned logical block can generate in response to a plurality of above-mentioned detecting device from above-mentioned a plurality of actuator units of above-mentioned current driver generate numerical data and supply to the input terminal of above-mentioned D/A transducer;

Above-mentioned D/A transducer can generate aanalogvoltage and supply to above-mentioned DC-DC transducer as reference voltage in response to above-mentioned numerical data;

Above-mentioned logical block is through the renewal one by one of above-mentioned numerical data; Carry out to confirm the calibration operation of above-mentioned numerical data, this numerical data is used for setting from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices minimum above-mentioned output dc voltage during the above-mentioned unusual whole raceway groove operate as normal of not shown above-mentioned drive current all.

2. SIC (semiconductor integrated circuit) as claimed in claim 1 is characterized in that:

Before the above-mentioned calibration operation of execution, the above-mentioned numerical data that above-mentioned logical block handle is set predetermined initial value for supplies to the above-mentioned input terminal of above-mentioned D/A transducer, and above-mentioned then logical block begins the execution of above-mentioned calibration operation.

3. SIC (semiconductor integrated circuit) as claimed in claim 2 is characterized in that:

If drive the driving duration of work process preset time of above-mentioned a plurality of raceway grooves of above-mentioned light-emitting device array at above-mentioned current driver, then above-mentioned logical block is carried out above-mentioned calibration operation termly.

4. SIC (semiconductor integrated circuit) as claimed in claim 3 is characterized in that:

Before the above-mentioned execution of above-mentioned calibration operation; Above-mentioned logical block supplies to the above-mentioned numerical data of setting above-mentioned predetermined initial value for the above-mentioned input terminal of above-mentioned D/A transducer; When confirming the operate as normal of above-mentioned whole raceway grooves through the above-mentioned execution of above-mentioned calibration operation, above-mentioned logical block is set above-mentioned numerical data for than the above-mentioned predetermined little value of initial value one by one once more then;

Through after the operate as normal of above-mentioned execution above-mentioned whole raceway grooves unconfirmed of above-mentioned calibration operation the time, reset into the value of above-mentioned numerical data the value under the state of the last operate as normal of having confirmed above-mentioned whole raceway grooves.

5. SIC (semiconductor integrated circuit) as claimed in claim 3 is characterized in that:

Above-mentioned each actuator unit in above-mentioned a plurality of actuator unit also comprises differential amplifier; In this differential amplifier; Non-inverting input is supplied to reference voltage; Reversed input terminal is connected with the common terminal of above-mentioned driving transistors, and lead-out terminal is connected with control input end of above-mentioned driving transistors;

Between the above-mentioned common terminal of the above-mentioned reversed input terminal of the above-mentioned differential amplifier of above-mentioned each actuator unit and above-mentioned driving transistors and earthing potential, be made as and be connected constant current and set resistance;

Some connection the in above-mentioned control input end of input terminal of the above-mentioned detecting device of above-mentioned each actuator unit and above-mentioned driving transistors and the above-mentioned common terminal, supply with detection judgment standard voltage to another input terminal of the above-mentioned detecting device of above-mentioned each actuator unit.

6. SIC (semiconductor integrated circuit) as claimed in claim 3 is characterized in that:

Above-mentioned logical block comprises: preserve above-mentioned numerical data value counter and in response to from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices and upgrade the control part of the value of the above-mentioned numerical data of preserving in the above-mentioned counter one by one.

7. SIC (semiconductor integrated circuit) as claimed in claim 6 is characterized in that:

Above-mentioned logical block also comprises the light adjusting controller that generates a plurality of light modulation pulse width modulated driving signal;

Utilization activates above-mentioned a plurality of actuator unit from above-mentioned a plurality of light modulation pulse width modulated driving signal that above-mentioned light adjusting controller generates.

8. SIC (semiconductor integrated circuit) as claimed in claim 7 is characterized in that:

Above-mentioned light adjusting controller utilization disperses type of drive to generate above-mentioned a plurality of light modulation pulse width modulated driving signal constantly in mutual different generation.

9. SIC (semiconductor integrated circuit) as claimed in claim 8 is characterized in that:

Above-mentioned DC-DC transducer is made as and can be connected with inductor, power MOS transistor, smmothing capacitor in the outside of above-mentioned SIC (semiconductor integrated circuit);

Above-mentioned DC-DC transducer is through drive above-mentioned power MOS transistor repeatedly during connecting and between the off period, above-mentioned DC-DC transducer generates above-mentioned output dc voltage.

10. SIC (semiconductor integrated circuit) as claimed in claim 9 is characterized in that:

Above-mentioned a plurality of actuator units of above-mentioned current driver are made as above-mentioned a plurality of raceway grooves that can drive the above-mentioned light-emitting device array that is made up of a plurality of light emitting diodes with PN junction.

11. a plurality of raceway grooves that the method for work of a SIC (semiconductor integrated circuit), this SIC (semiconductor integrated circuit) can the parallel drive light-emitting device arrays is characterized in that:

Above-mentioned DC-DC transducer is supplied with jointly to a plurality of ends of above-mentioned a plurality of raceway grooves of above-mentioned light-emitting device array and is boosted the input dc voltage or step-down and the output dc voltage that generates;

12. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 11 is characterized in that:

13. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 12 is characterized in that:

14. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 13 is characterized in that:

15. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 13 is characterized in that:

Above-mentioned each actuator unit of above-mentioned a plurality of actuator units also comprises differential amplifier; In this differential amplifier; Non-inverting input is supplied to reference voltage; Reversed input terminal is connected with the common terminal of above-mentioned driving transistors, and lead-out terminal is connected with control input end of above-mentioned driving transistors;

Between the above-mentioned common terminal of the above-mentioned reversed input terminal of the above-mentioned differential amplifier of above-mentioned each actuator unit and above-mentioned driving transistors and earthing potential, be connected constant current and set resistance;

16. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 13 is characterized in that:

Above-mentioned logical block comprises: preserve above-mentioned numerical data value counter and in response to from above-mentioned a plurality of detection signals of above-mentioned a plurality of detecting devices and upgrade the counter controls portion of the value of the above-mentioned numerical data of preserving in the above-mentioned counter one by one.

17. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 16 is characterized in that:

18. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 17 is characterized in that:

19. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 18 is characterized in that:

20. the method for work of SIC (semiconductor integrated circuit) as claimed in claim 19 is characterized in that: